Ultrafast tunable lasers using lithium niobate integrated photonics.

Early works1 and recent advances in thin-film lithium niobate (LiNbO3) on insulator have enabled low-loss photonic integrated circuits2,3, modulators with improved half-wave voltage4,5, electro-optic frequency combs6 and on-chip electro-optic devices, with applications ranging from microwave photonics to microwave-to-optical quantum interfaces7. Although recent advances have demonstrated tunable integrated lasers based on LiNbO3 (refs. 8,9), the full potential of this platform to demonstrate frequency-agile, narrow-linewidth integrated lasers has not been achieved. Here we report such a laser with a fast tuning rate based on a hybrid silicon nitride (Si3N4)-LiNbO3 photonic platform and demonstrate its use for coherent laser ranging. Our platform is based on heterogeneous integration of ultralow-loss Si3N4 photonic integrated circuits with thin-film LiNbO3 through direct bonding at the wafer level, in contrast to previously demonstrated chiplet-level integration10, featuring low propagation loss of 8.5 decibels per metre, enabling narrow-linewidth lasing (intrinsic linewidth of 3 kilohertz) by self-injection locking to a laser diode. The hybrid mode of the resonator allows electro-optic laser frequency tuning at a speed of 12 × 1015 hertz per second with high linearity and low hysteresis while retaining the narrow linewidth. Using a hybrid integrated laser, we perform a proof-of-concept coherent optical ranging (FMCW LiDAR) experiment. Endowing Si3N4 photonic integrated circuits with LiNbO3 creates a platform that combines the individual advantages of thin-film LiNbO3 with those of Si3N4, which show precise lithographic control, mature manufacturing and ultralow loss11,12.

A photonic integrated continuous-travelling-wave parametric amplifier.

The ability to amplify optical signals is of pivotal importance across science and technology typically using rare-earth-doped fibres or gain media based on III-V semiconductors. A different physical process to amplify optical signals is to use the Kerr nonlinearity of optical fibres through parametric interactions1,2. Pioneering work demonstrated continuous-wave net-gain travelling-wave parametric amplification in fibres3, enabling, for example, phase-sensitive (that is, noiseless) amplification4, link span increase5, signal regeneration and nonlinear phase noise mitigation6. Despite great progress7-15, all photonic integrated circuit-based demonstrations of net parametric gain have necessitated pulsed lasers, limiting their practical use. Until now, only bulk micromachined periodically poled lithium niobate (PPLN) waveguide chips have achieved continuous-wave gain16,17, yet their integration with silicon-wafer-based photonic circuits has not been shown. Here we demonstrate a photonic-integrated-circuit-based travelling-wave optical parametric amplifier with net signal gain in the continuous-wave regime. Using ultralow-loss, dispersion-engineered, metre-long, Si3N4 photonic integrated circuits18 on a silicon chip of dimensions 5 × 5 mm2, we achieve a continuous parametric gain of 12 dB that exceeds both the on-chip optical propagation loss and fibre-chip-fibre coupling losses in the telecommunication C band. Our work demonstrates the potential of photonic-integrated-circuit-based parametric amplifiers that have lithographically controlled gain spectrum, compact footprint, resilience to optical feedback and quantum-limited performance, and can operate in the wavelength ranges from visible to mid-infrared and outside conventional rare-earth amplification bands.

Integrated photonics enables continuous-beam electron phase modulation.

Integrated photonics facilitates extensive control over fundamental light-matter interactions in manifold quantum systems including atoms1, trapped ions2,3, quantum dots4 and defect centres5. Ultrafast electron microscopy has recently made free-electron beams the subject of laser-based quantum manipulation and characterization6-11, enabling the observation of free-electron quantum walks12-14, attosecond electron pulses10,15-17 and holographic electromagnetic imaging18. Chip-based photonics19,20 promises unique applications in nanoscale quantum control and sensing but remains to be realized in electron microscopy. Here we merge integrated photonics with electron microscopy, demonstrating coherent phase modulation of a continuous electron beam using a silicon nitride microresonator. The high-finesse (Q0 ≈ 106) cavity enhancement and a waveguide designed for phase matching lead to efficient electron-light scattering at extremely low, continuous-wave optical powers. Specifically, we fully deplete the initial electron state at a cavity-coupled power of only 5.35 microwatts and generate >500 electron energy sidebands for several milliwatts. Moreover, we probe unidirectional intracavity fields with microelectronvolt resolution in electron-energy-gain spectroscopy21. The fibre-coupled photonic structures feature single-optical-mode electron-light interaction with full control over the input and output light. This approach establishes a versatile and highly efficient framework for enhanced electron beam control in the context of laser phase plates22, beam modulators and continuous-wave attosecond pulse trains23, resonantly enhanced spectroscopy24-26 and dielectric laser acceleration19,20,27. Our work introduces a universal platform for exploring free-electron quantum optics28-31, with potential future developments in strong coupling, local quantum probing and electron-photon entanglement.

Monolithic piezoelectric control of soliton microcombs.

High-speed actuation of laser frequency1 is critical in applications using lasers and frequency combs2,3, and is a prerequisite for phase locking, frequency stabilization and stability transfer among optical carriers. For example, high-bandwidth feedback control of frequency combs is used in optical-frequency synthesis4, frequency division5 and optical clocks6. Soliton microcombs7,8 have emerged as chip-scale frequency comb sources, and have been used in system-level demonstrations9,10. Yet integrated microcombs using thermal heaters have limited actuation bandwidths11,12 of up to 10 kilohertz. Consequently, megahertz-bandwidth actuation and locking of microcombs have only been achieved with off-chip bulk component modulators. Here we demonstrate high-speed soliton microcomb actuation using integrated piezoelectric components13. By monolithically integrating AlN actuators14 on ultralow-loss Si3N4 photonic circuits15, we demonstrate voltage-controlled soliton initiation, tuning and stabilization with megahertz bandwidth. The AlN actuators use 300 nanowatts of power and feature bidirectional tuning, high linearity and low hysteresis. They exhibit a flat actuation response up to 1 megahertz-substantially exceeding bulk piezo tuning bandwidth-that is extendable to higher frequencies by overcoming coupling to acoustic contour modes of the chip. Via synchronous tuning of the laser and the microresonator, we exploit this ability to frequency-shift the optical comb spectrum (that is, to change the comb's carrier-envelope offset frequency) and make excursions beyond the soliton existence range. This enables a massively parallel frequency-modulated engine16,17 for lidar (light detection and ranging), with increased frequency excursion, lower power and elimination of channel distortions resulting from the soliton Raman self-frequency shift. Moreover, by modulating at a rate matching the frequency of high-overtone bulk acoustic resonances18, resonant build-up of bulk acoustic energy allows a 14-fold reduction of the required driving voltage, making it compatible with CMOS (complementary metal-oxide-semiconductor) electronics. Our approach endows soliton microcombs with integrated, ultralow-power and fast actuation, expanding the repertoire of technological applications of microcombs.

Integrated turnkey soliton microcombs.

Optical frequency combs have a wide range of applications in science and technology1. An important development for miniature and integrated comb systems is the formation of dissipative Kerr solitons in coherently pumped high-quality-factor optical microresonators2-9. Such soliton microcombs10 have been applied to spectroscopy11-13, the search for exoplanets14,15, optical frequency synthesis16, time keeping17 and other areas10. In addition, the recent integration of microresonators with lasers has revealed the viability of fully chip-based soliton microcombs18,19. However, the operation of microcombs requires complex startup and feedback protocols that necessitate difficult-to-integrate optical and electrical components, and microcombs operating at rates that are compatible with electronic circuits-as is required in nearly all comb systems-have not yet been integrated with pump lasers because of their high power requirements. Here we experimentally demonstrate and theoretically describe a turnkey operation regime for soliton microcombs co-integrated with a pump laser. We show the appearance of an operating point at which solitons are immediately generated by turning the pump laser on, thereby eliminating the need for photonic and electronic control circuitry. These features are combined with high-quality-factor Si3N4 resonators to provide microcombs with repetition frequencies as low as 15 gigahertz that are fully integrated into an industry standard (butterfly) package, thereby offering compelling advantages for high-volume production.

Mechanistic Insights into the N-Hydroxylations Catalyzed by the Binuclear Iron Domain of SznF Enzyme: Key Piece in the Synthesis of Streptozotocin.

SznF, a member of the emerging family of heme-oxygenase-like (HO-like) di-iron oxidases and oxygenases, employs two distinct domains to catalyze the conversion of Nω-methyl-L-arginine (L-NMA) into N-nitroso-containing product, which can subsequently be transformed into streptozotocin. Using unrestricted density functional theory (UDFT) with the hybrid functional B3LYP, we have mechanistically investigated the two sequential hydroxylations of L-NMA catalyzed by SznF's binuclear iron central domain. Mechanism B primarily involves the O-O bond dissociation, forming Fe(IV)=O, induced by the H+/e- introduction to the FeA side of µ-1,2-peroxo-Fe2(III/III), the substrate hydrogen abstraction by Fe(IV)=O, and the hydroxyl rebound to the substrate N radical. The stochastic addition of H+/e- to the FeB side (mechanism C) can transition to mechanism B, thereby preventing enzyme deactivation. Two other competing mechanisms, involving the direct O-O bond dissociation (mechanism A) and the addition of H2O as a co-substrate (mechanism D), have been ruled out.

Activation and Conversion of Methane to Syngas over ZrO2/Cu(111) Catalysts near Room Temperature.

Enzymatic systems achieve the catalytic conversion of methane at room temperature under mild conditions. In this study, varying thermodynamic and kinetic parameters, we show that the reforming of methane by water (MWR, CH4 + H2O → CO + 3H2) and the water-gas shift reaction (WGS, CO + H2O → H2 + CO2), two essential processes to integrate fossil fuels toward a H2 energy loop, can be achieved on ZrO2/Cu(111) catalysts near room temperature. Measurements of ambient-pressure X-ray photoelectron spectroscopy and mass spectrometry, combined with density functional calculations and kinetic Monte Carlo simulations, were used to study the behavior of the inverse oxide/metal catalysts. The superior performance is associated with a unique zirconia-copper interface, where multifunctional sites involving zirconium, oxygen, and copper work coordinatively to dissociate methane and water at 300 K and move forward the MWR and WGS processes.

Plastome evolution and phylogenomics of Impatiens (Balsaminaceae).

MAIN CONCLUSION: This study reported seven new plastomes from Impatiens and observed three highly variable regions for phylogeny and DNA barcoding, which resolved the relationships among sections of subgenus Impatiens. Impatiens L. (Balsaminaceae, Ericales) is one of the largest and most diverse genera of angiosperms, widely known for its taxonomic difficulty. In this study, we reevaluated the infrageneric relationships within the genus Impatiens, using complete plastome sequence data. Seven complete plastomes of Impatiens (representing 6 species) were newly sequenced and characterized along with 20 previously published plastomes of other Impatiens species, plus 2 plastomes of outgroups (Hydrocera triflora, Balsaminaceae; Marcgravia coriacea, Marcgraviaceae). The total size of these 29 plastomes ranged from 151,538 bp to 152,917 bp, except 2 samples of Impatiens morsei, which exhibited a shorter length and lost some genes encoding NADH dehydrogenase subunits. Moreover, the number of simple sequence repeats (SSRs) ranged from 51 to 113, and the number of long repeats from 17 to 26. In addition, three highly variable regions were identified (trnG-GCC (The previous one), ndhF-rpl32-trnL-UGA-ccsA, and ycf1). Our phylogenomic analysis based on 80 plastome-derived protein-coding genes strongly supported the monophyly of Impatiens and its two subgenera (Clavicarpa and Impatiens), and fully resolved relationships among the six (out of seven) sampled sections of subgenus Impatiens. Overall, the plastome DNA markers and phylogenetic results reported in this study will facilitate future identification, taxonomic and DNA barcoding studies in Impatiens as well as evolutionary studies in Balsaminaceae.

Predictive Value of the Hepatic Immune Predictive Index for Patients with Primary Liver Cancer Treated with Immune Checkpoint Inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have improved survival outcomes and resulted in long-term responses in primary liver cancer in some patients. Nevertheless, not all patients with PLC could benefit from immunotherapy. Therefore, it is necessary to identify patients suitable for such therapy. METHODS: 215 patients with primary liver cancer with immunotherapy from Nanfang Hospital were screened between August 2018 and October 2020 as a training set and our validation set included 71 patients of hepatocellular carcinoma from Jiangxi Cancer Hospital from May 2019 to July 2021. The primary endpoint was the disease control rate (DCR), and the secondary endpoints were overall survival (OS) and progression-free survival. RESULTS: In the training set, neutrophil-lymphocyte ratio (NLR) ≥3 and alpha-fetoprotein (AFP) level ≥20 ng/mL were independently associated with non-DCR in the training set after adjusting for distant metastasis at baseline and targeted therapy combination. Furthermore, a hepatic immune predictive index (HIPI) based on NLR and AFP level was developed and patients with poor HIPI associated with worse clinical outcomes. In validation set, high HIPI was associated with poor OS. CONCLUSION: HIPI, based on NLR and AFP level, is an effective indicator in ICI-treated patients with primary liver cancer. Our findings may help guide the selection and on-treatment strategies for immunotherapies for primary liver cancer patients.

Patterned 2D Ferroelectric Perovskite Single-Crystal Arrays for Self-Powered UV Photodetector Boosted by Combining Ferro-Pyro-Phototronic and Piezo-Phototronic Effects.

Metal halide perovskite ferroelectrics possess various physical characteristics such as piezoelectric and pyroelectric effects, which could broaden the application of perovskite ferroelectrics and enhance the optoelectronic performance. Therefore, it is promising to combine multiple effects to optimize the performance of the self-powered PDs. Herein, patterned 2D ferroelectric perovskite (PMA)2PbCl4 microbelt arrays were demonstrated through a PDMS template-assisted antisolvent crystallization method. The perovskite arrays based flexible photodetectors exhibited fine self-powered photodetection performance under 320 nm illumination and much enhanced reproducibility compared with the randomly distributed single-crystal microbelts-based PDs. Furthermore, by introducing the piezo-phototronic effect, the performance of the flexible PD was greatly enhanced. Under an external tensile strain of 0.71%, the responsivity was enhanced by 185% from 84 to 155.5 mA/W. Our findings offer the advancement of comprehensively utilizing various physical characteristics of the ferroelectrics for novel ferroelectric optoelectronics.

Use of computed tomography-derived body composition to determine the prognosis of patients with primary liver cancer treated with immune checkpoint inhibitors: a retrospective cohort study.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have been used to successfully treat primary liver cancer (PLC); however, identifying modifiable patient factors associated with therapeutic benefits is challenging. Obesity is known to be associated with increased survival after ICI treatment; however, the relationship between body composition (muscle, fat) and outcomes is unclear. This study aimed to evaluate the association between sarcopenia and CT-derived fat content and the prognosis of ICIs for the treatment of PLC. METHODS: In this retrospective cohort study of 172 patients with PLC, we measured the skeletal muscle index (SMI), skeletal muscle density, visceral adipose tissue index, subcutaneous adipose tissue index, total adipose tissue index (TATI), and visceral-to-subcutaneous adipose tissue area ratio using CT. In addition, we analyzed the impact of body composition on the prognosis of the patients. Multivariate Cox regression analysis was used to screen for influencing factors. RESULTS: Among the seven body composition components, low SMI (sarcopenia) and low TATI were significantly associated with poor clinical outcomes. Multivariate analysis revealed that sarcopenia (hazard ratio [HR], 5.39; 95% confidence interval [CI], 1.74-16.74; p = 0.004) was a significant predictor of overall survival (OS). Kaplan-Meier curves showed that sarcopenia and TATI were significant predictors of OS. Body mass index was not associated with survival outcomes. CONCLUSIONS: Sarcopenia and fat tissue content appear to be independently associated with reduced survival rates in patients with PLC treated with ICIs.

Breakfast consumption frequency is associated with dyslipidemia: a retrospective cohort study of a working population.

BACKGROUND: Dyslipidemia is a significant contributor to cardiovascular and cerebrovascular diseases. Research on the relationship between breakfast consumption frequency and dyslipidemia in the working population is lacking. Therefore, we aimed to investigate this relationship based on a retrospective cohort study of a large working population in China. METHODS: This retrospective cohort study used data from the physical examinations and questionnaire survey of working participants at Nanfang Hospital from January 20, 2015 to October 16, 2020. Univariate and multivariate analyses were conducted to explore the relationship between breakfast consumption frequency and dyslipidemia in this working population (n = 7644). RESULTS: The prevalence of dyslipidemia among the participants was 26.4%. The univariate logistic regression test showed that the breakfast consumption frequency was inversely correlated with dyslipidemia. After adjusting for multiple factors, such as sex, age, body mass index, hypertension, hyperuricaemia, diabetes, smoking status, alcohol consumption, education level, marital status, long-term exposure to kitchen oil fumes, attending business dinners, and sleep time, it was found that breakfast consumption remained inversely associated with dyslipidaemia. The odds ratio for daily breakfast consumption was 0.466 (95% confidence interval 0.283-0.770, P = 0.003). After adjusting for confounding factors, we found that the higher the frequency of breakfast consumption, the lower the odds ratios for hypertriglyceridaemia. CONCLUSIONS: This study demonstrated that breakfast consumption frequency was inversely correlated with dyslipidemia. The higher the frequency of breakfast, the lower the risk of hypertriglyceridaemia. This study provides a basis on which dietary suggestions for the working population and lifestyle guidance for patients with a clinical need to prevent dyslipidemia can be made.

Low-Loss Integrated Nanophotonic Circuits with Layered Semiconductor Materials.

Monolayer transition-metal dichalcogenides with direct bandgaps are emerging candidates for optoelectronic devices, such as photodetectors, light-emitting diodes, and electro-optic modulators. Here we report a low-loss integrated platform incorporating molybdenum ditelluride monolayers with silicon nitride photonic microresonators. We achieve microresonator quality factors >3 × 106 in the telecommunication O- to E-bands. This paves the way for low-loss, hybrid photonic integrated circuits with layered semiconductors, not requiring heterogeneous wafer bonding.

Surface characterization and methane activation on SnOx/Cu2O/Cu(111) inverse oxide/metal catalysts.

To activate methane at low or medium temperatures is a difficult task and a pre-requisite for the conversion of this light alkane into high value chemicals. Herein, we report the preparation and characterizations of novel SnOx/Cu2O/Cu(111) interfaces that enable low-temperature methane activation. Scanning tunneling microscopy identified small, well-dispersed SnOx nanoclusters on the Cu2O/Cu(111) substrate with an average size of 8 Å, and such morphology was sustained up to 450 K in UHV annealing. Ambient pressure X-ray photoelectron spectroscopy showed that hydrocarbon species (CHx groups), the product of methane activation, were formed on SnOx/Cu2O/Cu(111) at a temperature as low as 300 K. An essential role of the SnOx-Cu2O interface was evinced by the SnOx coverage dependence. Systems with a small amount of tin oxide, 0.1-0.2 ML coverage, produced the highest concentration of adsorbed CHx groups. Calculations based on density functional theory showed a drastic reduction in the activation barrier for C-H bond cleavage when going from Cu2O/Cu(111) to SnOx/Cu2O/Cu(111). On the supported SnOx, the dissociation of methane was highly exothermic (ΔE∼-35 kcal mol-1) and the calculated barrier for activation (∼20 kcal mol-1) could be overcome at 300-500 K, target temperatures for the conversion of methane to high value chemicals.

Strain-driven phase transition and spin polarization of Re-doped transition-metal dichalcogenides.

Two-dimensional transition metal dichalcogenides (TMDCs) are promising in spintronics due to their spin-orbit coupling, but their intrinsic non-magnetic properties limit their further development. Here, we focus on the energy landscapes of TMDC (MX2, M = Mo, W and X = S, Se, Te) monolayers by rhenium (Re) substitution doping under axial strains, which controllably drive 1H ↔ 1Td structural transformations. For both 1H and 1Td phases without strain, Re-doped TMDCs have an n-type character and are non-magnetic, but the tensile strain could effectively induce and modulate the magnetism. Specifically, 1H-Re0.5Mo0.5S2 gets a maximum magnetic moment of 0.69 µB at a 6% uniaxial tensile strain along the armchair direction; along the zigzag direction it exhibits a significant magnetic moment (0.49 µB) at a 2.04% uniaxial tensile strain but then exhibits no magnetism in the range of [5.10%, 7.14%]. By contrast, for 1Td-Re0.5Mo0.5S2 a critical uniaxial tensile strain along the zigzag direction reaches up to ∼9.18%, and a smaller uniaxial tensile strain (∼5.10%) along the zigzag direction is needed to induce the magnetism in 1Td-Re0.5M0.5Te2. The results reveal that the magnetism of Re-doped TMDCs could be effectively induced and modulated by the tensile strain, suggesting that strain engineering could have significant applications in doped TMDCs.

Modulating Single-Atom Palladium Sites with Copper for Enhanced Ambient Ammonia Electrosynthesis.

The electrochemical reduction of N2 to NH3 is emerging as a promising alternative for sustainable and distributed production of NH3 . However, the development has been impeded by difficulties in N2 adsorption, protonation of *NN, and inhibition of competing hydrogen evolution. To address the issues, we design a catalyst with diatomic Pd-Cu sites on N-doped carbon by modulation of single-atom Pd sites with Cu. The introduction of Cu not only shifts the partial density of states of Pd toward the Fermi level but also promotes the d-2π* coupling between Pd and adsorbed N2 , leading to enhanced chemisorption and activated protonation of N2 , and suppressed hydrogen evolution. As a result, the catalyst achieves a high Faradaic efficiency of 24.8±0.8 % and a desirable NH3 yield rate of 69.2±2.5 µg h-1 mgcat. -1 , far outperforming the individual single-atom Pd catalyst. This work paves a pathway of engineering single-atom-based electrocatalysts for enhanced ammonia electrosynthesis.

Chip-based soliton microcomb module using a hybrid semiconductor laser.

Photonic chip-based soliton microcombs have shown rapid progress and have already been used in many system-level applications. There has been substantial progress in realizing soliton microcombs that rely on compact laser sources, culminating in devices that only utilize a semiconductor gain chip or a self-injection-locked laser diode as the pump source. However, generating single solitons with electronically detectable repetition rates from a compact laser module has remained challenging. Here we demonstrate a current-initiated, Si3N4 chip-based, 99-GHz soliton microcomb driven directly by a compact, semiconductor-based laser. This approach does not require any complex soliton tuning techniques, and single solitons can be accessed by tuning the laser current. Further, we demonstrate a generic, simple, yet reliable, packaging technique to facilitate the fiber-chip interface, which allows building a compact soliton microcomb package that can benefit from the fiber systems operating at high power (> 100 mW). Both techniques can exert immediate impact on chip-based nonlinear photonic applications that require high input power, high output power, and interfacing chip-based devices to mature fiber systems.

Observation of Stimulated Brillouin Scattering in Silicon Nitride Integrated Waveguides.

Silicon nitride (Si_{3}N_{4}) has emerged as a promising material for integrated nonlinear photonics and has been used for broadband soliton microcombs and low-pulse-energy supercontinuum generation. Therefore, understanding all nonlinear optical properties of Si_{3}N_{4} is important. So far, only stimulated Brillouin scattering (SBS) has not yet been reported. Here we observe, for the first time, backward SBS in fully cladded Si_{3}N_{4} waveguides. The Brillouin gain spectrum exhibits an unusual multipeak structure resulting from hybridization with high-overtone bulk acoustic resonances of the silica cladding. The reported intrinsic Si_{3}N_{4} Brillouin gain at 25 GHz is estimated as 4×10^{-13} m/W. Moreover, the magnitude of the Si_{3}N_{4} photoelastic constant is estimated as |p_{12}|=0.047±0.004, which is nearly 6 times smaller than for silica. Since SBS imposes an optical power limitation for waveguides, our results explain the capability of Si_{3}N_{4} to handle high optical power, central for integrated nonlinear photonics.

Protoilludane-type sesquiterpenoids from Armillaria sp. by co-culture with the endophytic fungus Epicoccumsp. associated with Gastrodia elata.

An investigation of a co-culture of the Armillaria sp. and endophytic fungus Epicoccum sp. YUD17002 associated with Gastrodia elata led to the isolation of eight new compounds, including five protoilludane-type sesquiterpenes (1-5) and three aryl esters (6-8), together with six known analogues (9-14). The assignments of their structures were conducted via extensive analyses of the spectroscopic data and comparison of experimental and calculatedelectronic circular dichroism(ECD)data. Notably, these new compounds were not present in the pure culture controls and were only detected in the co-cultures. Compound 4 is the first example of an ent-protoilludane sesquiterpenoid scaffold bearing a five-membered lactone. Compound 6 exhibited moderate in vitro cytotoxic activities against five human cancer cell lines (HL-60, A549, MCF-7, SMMC-7721, and SW480) with IC50 values ranging from 15.80 to 23.03 µM. Moreover, 6 showed weak acetylcholinesterase inhibitory activity (IC50 value of 23.85 µM).

Growth and structural studies of In/Au(111) alloys and InOx/Au(111) inverse oxide/metal model catalysts.

Indium oxide has received attention as an exciting candidate for catalyzing the CO2 hydrogenation to methanol due to its high selectivity (>80%). Compared to the extent of research on the activity of indium oxide-based powder catalysts, very little is known about the phenomena associated with the formation of surface alloys involving indium or the growth mechanism for indium oxide nanoparticles. In this report, scanning tunneling microscopy and X-ray photoelectron spectroscopy (XPS) were employed to elucidate the growth mode, structure, and chemical state of In/Au(111) alloys and InOx/Au(111) inverse model catalysts. Our study reveals distinct morphological differences between In/Au(111) and InOx/Au(111), and the InOx structure also depends strongly on the preparation conditions. In/Au surface alloy systems with extremely low coverage (0.02 ML) form islands preferentially on the elbow sites of reconstructed Au(111) herringbone, regardless of hexagonally closed packed and face centered cubic stacking. At higher coverage (0.1 ML), the In islands expand over the herringbone in the ⟨110⟩ direction and create two dimensional domain structures over the entire surfaces. Moreover, this 2D domain structure is disturbed by temperature with high dispersion of indium atoms observed during the annealing process. Oxidation of the In/Au(111) surface alloys with O2 at 550 K produces InOx/Au(111) systems which contain various sizes of InOx aggregates (from 0.7 nm to 10 nm). On the other hand, InOx/Au(111) surfaces prepared by vapor deposition of In at 550 K in an O2 background exhibit highly dispersed and uniformly small InOx particles (∼1 nm). Both InOx systems were confirmed to be partially oxidized by XPS.